Internal combustion engine



Sept. i7, 1935. P. scHlvlALJol-mNN l l 2,914,672.

` INTERNAL COMBUSTION ENGINE Filed July 2l, 1933 2 Sheets-Sheet l Sepp 17,' 1935?.

P. SCHMALJOHANN INTERNAL COMBUSTION ENGINE Filed Julyy 2l, 1933 2 Sheets-Sheet 2 7n-Verbier P fof/ma/ 127 l'lat-enteci Sept. i7,-

INTERNAL oonnnsfrroNnNelNn PauiSchm-aljohann, Kiel, Germany, assigner, by

mesne assignments, to Centra Handels- &" Industrie A.G., Chur, Switzerland Application July 2l, 1933,"Serial No.f681,623 in Germany `lully 27, 1932.

10 Claims.

` VMy'invention relates to improvements in internal combustion engines, and more particularly fin engines of the Ytype in `which three or more cylinders are'disposed radially of each other, so

f5 as to provide a Vcommon combustion chamber, and

ject'in View my invention consists in constructing `'the roof-shaped l(the, significance of which term has'been explained hereinbefore) ends of the pistons lso that a compact combustionfchamber is provided in which the fuel is thoroughly mixed with the'icompressed air, land into 'whichthe fuel "is injected'through a passage provided between two h faces of adjacent pistons. ByA thus"v constructing the combustion chamber and the means forinjecting the fuel, the said fuel impinges upon :the end faces of theipistonslocated opposite to 'the nozzle, andit is raised to ignition temperature Within the combustion chamber. Thus the fuel is uniformly distributed all through the combustion chamber, 's o that complete combustion within the `said combustion chamber is insured. addition the fuel which is still Withinthe passage in frontA of the nozzle is'likewise ignited,` because by theignition within Vthev combustion chamber a body of gasv is forced from-the ignition-chamber into the said-passage and in opposition to the jet Iof fuel being injected. Thus the saidportion of vfthe fuel which' is nwithinthe passage in front of `fthe nozzleI and a certainamount ofcompressed 'air are forced into the passage and'ignted there- 1n. Y f `For the purpose of explaining the invention several examples'embodying'the same have been l f shown in the'V accompanying drawings "inlwhich the same reference characters vhave' been used in all the views` to indicate 'Correspendingjglarts.Y In fsaid'drawi'ngs Fig."1 is a`diagrammaticalsectional-elevation l"showing the cylinders and'pistons, the gearing connected with `theti-pistons,' and thei fuel' pump,

t "FigJ 2 `is a sectional elevation taken on` the lL "55""1ine' 2`2 Of-Fig. 1.

(Cl. 12S-5l) Fig. 3 visa fragmentary sectional lelevation showing a modification,

Fig. 4 is-a sectional elevationtakenl on the line li--4 of Fig. 3,

Fig. 5 is a fragmentary perspective View of the example shown in Figs, 3 and 4, one ofthev pistons being removed,

Figs.- 6 and l are fragmentary sectional'elevations showing other modifications,

Fig. 8 is a similar fragmentaryelevation showl0 ing a modification which is 'similar to. the example illustrated in Figs. 3 to 5,. and

Fig. 9 is a diagram showing the .velocity of the -fuel being injected.

In Figs. 1 and 2, I have shown a two-stroke15 cycle internalicombustion engine, comprising a body i composed of three cylinders 2', 2 and 3 disposed star-like and radially of one another, .and pistons 4, 5, the cylinders 2, 2 `being `provided Y with slots 6, t for the Aadmission `of scavenging air, Se

andl the .cylinder 3 being provided with slots l for `the exhaust of the gases of combustion. The Y Ypistons are connected with cranks 8, 8, 9 Ycooperating with gear Wheels it, Il as is known inthe art.

V`In Fig l the pistons are shown in their inner 'deadijcentera and they provide a :common combustion chamber betweenitheiihend. faces. The end iface of each pistontcomprises twobevelled planes il? and i3 disposedinthe roof-like manner 3o explained hereinbefore, so that thetzspace between theiends of thepist-ons is reduced in size. `Between thev cylinders 2 of the pistons controlling theadmission of. scavenging air a .fuel injection passage is is-provided coaxially of the 35 piston controlling the exhaust.

Fuel issupplied to the nozzle lli through a pipe lconnectedwith thefpressure chamber of a fuel Apump l iS-thesuction .chamber -of which is connectedfbyiapipe il with a fuel tank. .The plunger 4o le isoperatedby a cam'ilprovioledv on a shaft v 2t connected 'with theA accelerator.

The cylinder 3 of the piston 5 controlling the f'exhaust islextended, or the piston t3 is reduced in length so-that-a somewhatenlarged chamber22-45 is proVidedbetween-the end faces of the scavenging pistons {Lilland the exhaust controlling pisv`ton 5 'when' 44the' said. pistons are in their inner dead centersfthe.saidchamber 22 being broader than therfpassage 2i yprovided between the faces 50 "Eiland I3 of the' pistons 4, ll.

-l Injections begins near thelend of the compres- M sionstrokafland-lthefuel isv inj ectedll .through the narrow-passage Zi'and into -theichamber 22 con- #taininglfcompressed air.4 The chamber-22 com-55 prises two fiat portions disposed in roof-like maner, that is, in the form of an inverted V, and thus the jet of fuel is distributed to opposite sides and into the air contained in the flat portions of the chamber. When the pistons are in their inner dead centers as shown in Fig. 1, the pressure within the chamber 22 is at its maximum and the temperature of the mixture of air and fuel is higher than the ignition temperature of the fuel. Thus the mixture is ignited and completely burnt.

When the pistons are in their inner dead centers injection of fuel is interrupted. The amount of fuel which has last been injected through the nozzle lli and which is about to flow through the narrow passage 2 t and into the ignition charnber 22 is arrested by the gas within the chamber 22, which expands and flows into the passage 2i in opposition to the fuel injected into the same. Thus further movement of the particles of fuel which have last been injected is prevented, and the said particles are even forced backwardly into the part of the passage 2| which is adjacent to the nozzle. Within the said parts of the passage there is air under pressure which has not been consumed, because the previously injected fuel had been thrown into the inner part of the combustion chamber. Thus also the particles of fuel which have last been injected are completely burnt, and the engine operates with smokeless combustion even with very high speed.

The enlarged ignition chamber 22 may be provided also by reducing the scavenging pistons 4, 4 in length by retracting the end faces l2, I3 thereof away from the end face of the piston 5, in which case the slanting planes defining the end faces of the said pistons intersect on a line disposed laterally of the longitudinal center axis of the piston. Further, the pistons may be recessed at their ends.

In the modification shown in Figs. 3 to 5 the fuel passage 324 is provided between the scavenging pistons 384, 304 by providing the opposite faces 3|3 and 312 of the said pistons with corresponding grooves 323 located coaxially of the fuel nozzle 3M and flaring outwardly from the said nozzle towards the ignition chamber. When the pistons are in their inner dead centers the said grooves are combined into the fuel passage 326i which corresponds by its flaring shape to the form of the jet of fuel. The remaining portions of the end faces 352, 3 I3 of the pistons are brought close to each other when the pistons are in their inner dead centers, so that the dead space the air content of which cannot be made use of in the cornbustion is reduced to a minimum.

The piston 3ii5 controlling the exhaust is formed with a concave recess 335 disposed transversely of the ridge in which the roof -like faces 3|2 and 3 I3 end, the said recess having the form of a groove. The said recess provides the ignition chamber which is bounded by the recessed end face of the piston 3&5 and the faces 312 and 3|3 of the opposite pistons 3M.

In the construction shown in Figs. 1 and 2 in which the ignition chamber 22 comprises two portions, the fuel may not be uniformly distributed through the compressed air within the said portions, so that in some parts of the ignition chamber carbon monoxide might be produced by reason of a want of oxygen. In the construction shown in Figs. 3 to 5 in which the ignition chamber 325 is provided by the recess made in the end of the piston 395 the said ignition chamber takes the form of a single flat space. The fuel which is first injected passes through the passage 324 pro vided between the pistons 3M, 394, and it expands by reason of the flaring shape of the said passage, whereupon it gets into the compressed air within the chamber 325. Thus a large surface of the said body of air is directly impinged upon by the jet. By reason of the flat shape of the chamber 325 the fuel is uniformly distributed all through the chamber into the cuter corners thereof, so that by ignition at the time of highest compression complete combustion of the fuel is more effectively insured than in the construction described with reference to Figs. l and 2.

In Fig. 6 I have shown an engine comprising live cylinders. The fuel passage Elli is disposed between two cylinders 832 containing scavenging pistons @G and opposite to the piston 655 controlling the exhaust. The pistons adjacent to the piston 335 may likewise be pistons 5&4 controlling the supply of scavenging air. The exhaust controlling piston 665 is formed at its end with a recess 625 which provides the ignition chamber together with the opposing faces 652 and 6|3 of the adjacent pistons 664 controlling the supply of scavenging air. The passage 624 for the supply of fuel is provided by grooves made in the opposing end faces EZ, 6l3 of the pistons 60K! located at either side of the injection passage GM.

In the modification shown in Fig. 7 the engine comprises four cylinders. The fuel passage 'H4 is provided between two pistons '564 controlling the supply of scavenging air and opposite to the line where the cylinders 703 containing the exhaust controlling pistons meet. In the construction shown in the figure the ignition chamber is provided by recesses '125 made in the roof-shaped 55 ends of the exhaust controlling pistons 'i which are opposite to the pistons 'm4 controlling the supply of scavenging air, and by the faces l'Z, 'H3 of the said pistons. The passage 724 is provided by the opposing faces T52, 'H3 of the pistons 104 between which the fuel passage is located.

In the modification shown in Fig. 8 the fuel passage 854 does not directly open into the passage provided between the end faces of the pistons 834, but into a chamber 82S provided in the body between the said passage and the fuel nozzle, the said chamber 82S being the continuation of the passage 824 and having the nozzle 8M thereof opening into the same. The chamber 325 is surrounded by a cooling jacket 32?.

Within the passage 826 the jet of fuel is prepared for combustion. At the beginning of the injection and while the pistons BBG, 3M and @B5 perform their compression strokes a current of air is blown from the passage 824 into the chamber 825 in opposition to the jet of fuel. Thereby the jet of fuel is atomized within the chamber 825, particularly by friction on the current of air, so that it is effectively prepared for the following combustion.

The volume of fuel contained within the chamber 826 near the end of the injection is stowed within the said chamber by gas being driven in opposition to the jet of fuel at the end of the ignition from the ignition chamber 825, because the pressure wave produced within the ignition chamber 825 by ignition is transmitted through the passage 824 to the chamber 826. Thereby the fuel is distributed Within the chamber 825 and ignition is transmitted through the passage 824 to the chamber 826. Thereby the fuel is distributed within the chamber 826 and intimately mixed with the air and ignited.

The distribution of the air at the moment of highest compression is illustrated in the diagram 828"forminga 'part 'ofxFig. 8.#The abscissae in-I Yprovide only spaces for supplying the fuel to the combustion chamber.

In orderito prevent premature ignition'of the fuel within the chamber 826, the' said chamber `is provided with a cooling jacket 821 by means of whichA the temperature of the walls of the chamber is held below self-ignition temperature.

The cam I9 for operating the plunger I8 of the fuel pump l is constructed so that the injection is adapted to the combustion after ignition of the fuel within the ignition chamber 22 or 325. The cam le which rotates inthe direction of the arrow shown in Fig. l has an ascending surface compris-ed of two parts 29a and 2gb, and a longer descending surface Sil. The part 29a is considerably steeper than the part 29h. The shape of the cam corresponds to the diagram illustrated in Fig. 9, in which the line 3l indicates the ve-Y locity of the fuel injection. The velocities of the plunger i3 have been represented by the ordinates, while the time has been represented by the abscissae. The plunger i8 is forced upwardly at high velocity, so that at the beginning of the injection indicated by the point 32 of the line 3l the fuel is forced with high velocity through the passage 2A and into the ignition chamber 22 or 325. Thereafter the velocity of the plunger is rapidly reduced, until the injection is termi-- nated at the point 33. Therefore the particles of fuel which have last been injected get only to the passage 24, and the retarding action of the gas forced from the ignition chamber 275 into the passage 213 and in opposition to the jet of fuel during the last part ofthe injection is supported. The fuel particles remain near the nozzle of the fuel passage l ll and they iill the passage 24 which contains non-consumed oxygen. The exhaust passage may have a lead relatively to the pistons controlling the supply of scavenging air. The fuel nozzle may also be provided between a piston for supplying cooling air and a piston controlling the exhaust, or between two pistons controlling the exhaust.

By thus controlling the supply of'fuel to the combustion chamber, the pressure on the fuel being injected decreases from the beginning of the injection towards the end thereof, and the fuel is injected at first at high velocity, and at the end of the injection at low velocity. Therefore the particles of fuel which are last injected remain within the portion of the passage 82S which is adjacent to the fuel nozzle, where they find non-consumed air for supporting combustion.

I claim:

1. In an internal combustion engine, a plurality of cylinders the number of which is greater than two arranged star-like and having a common combustion chamber, pistons reciprocating within said cylinders and formed with rooflike end faces, a fuel injection nozzle between two adjacent cylinders, and gearing connected with said pistons and controllingV the movement thereof, the end faces of said pistons being shaped so that when the said pistons are in their inner dea'd centers betweenl thel end face of the piston opposite to the injection nozzle and the endfacesV of' tnetpistonsfv opposite to the saidzpiston anigniticn chamber is provided, and that between the end facesy of the pistons reciprocating within the cylinders having the -injection passage located betWeenthesame a passage is provided which connects the said nozzlev with said ignition chamber.

2. A ydevice Vaccording to claim 1,'in which the said ignition chamber is provided by having the end-'face cfthepistonI located opposite to the injection nozzle spaced from the end faces of the other pistons when the pistons are in their inner dead-centers.

13. VA device `according toiclaim 1,'-in which the piston opposite to the injection nozzle is formed at its inner end with a recess providing an ignition chamber.

4. A device according toclairn 1, in which the pistons meet in a line at their ends and in which the piston located opposite to the injection nozzle is formed with a recess in the form of a flat groove disposed transversely of the said line in which the faces of the pistons meet.

5. A device according to claim 1, in which the end faces of the pistons reciprocating within the cylinders having the fuel injection nozzle located between the same are formed with grooves which are disposed in the direction of the jet of fuel, and cooperating when the pistons are in their inner dead centers to provide a passage extending from the fuel injection nozzle to the ignition chamber.

6. A device ,according to claim 1, in which the end faces of the pistons reciprocating within the cylinders having the fuel injection nozzle located between the same are formed with grooves which are disposed in the direction of the jet of fuel, and aring outwardly from the circumference of the pistons to the axes thereof and cooperating when the pistons are in their inner dead centers to provide an outwardly flaring passage extending from the fuel injection nozzle to the ignition chamber.

7. A device according to claim 1, in which the end faces of the pistons reciprocating in the cylinders having said injection nozzle located betweenV the same are formed with grooves which are disposed in the direction of the jet of fuel, and cooperating when the pistons are in their inner dead centers to provide a passage located coaxially of said nozzle and extending from the circumference of the pistons towards the axes thereof, and in which device between the delivery end of the nozzle and the intake end of the said passage an enlarged chamber is provided in the body of the cylinder.

8. A device according to claim 1, in which the v end faces of the pistons reciprocating in the cylinders having said injection nozzle located between the same 4are formed with grooves which are disposed in the direction of the jet of fuel, and cooperating when the pistons are'in their inner dead centers to provide a passage located coaxially of said nozzle and extending from the circumference of the pistons towards the axes thereof, and in which device between the delivery end of the nozzle and the intake end of the said passage an enlarged chamber is provided in the Vbody of the cylinder, the part of the body of the cylinders around said chamber located between the nozzle and the said passage being formed with cooling means.

9. A device according to claim 1, comprising fuel injecting means adapted to inject the fuel under pressure which decreases from the beginning of the injection towards the end thereof.

10. In an internal combustion engine, comprising more than two cylinders disposed in`starlike fashion and defining between them a common combustion chamber, pistons reciprocating within said cylinders and formed with roof-like end faces so shaped that they partly ll the said combustion chamber when they are at their -1nner dead centers, a fuel injection nozzle between two adjacent cylinders, gearing connected with said pistons for transmitting the power impulses thereof, the shape of the roof-like end faces of said pistons being such that when the pistons are at their inner dead centers an ignition chamber is provided between the end face of that piston which is opposite to the injection nozzle and the end faces of those pistons which are opposite to the said last-mentioned pistons, and so that a passage is provided between the end faces of those pistons reciprocating Within the cylinders which have the injection passage located therebetween, and means defining an atomizing chamber between said nozzle and said passage, movement of the pistons towards dead center driving gas into said atomizing chamber against the jet of fuel to atomize the same, and the said passage connecting said atomizing chamber with said ignition chamber. 

